Abstract

Growth conditions for AlN in two dimensional (2D) and three dimensional (3D) growth modes were explored on SiC using metal organic chemical vapor deposition. High quality AlN layers were obtained by alternating between 3D and 2D growth modes, referred to as modulation growth(MG). Long parallel atomic terraces without step terminations were observed in atomic force microscopy(AFM) scans of MGAlN, indicating a reduced dislocation density. X-ray diffraction rocking curves yielded full widths at half maximum (FWHM) of 86 and for the (002) and (102) reflections, respectively, giving further evidence of low dislocation density in the film. 3D-2D MG also releases some of the tensile strain in the AlN film, enabling the growth of thick, crack-free AlN on SiC substrates.